A vaccine can help keep people healthy and protect them from a certain virus. For example people in the United States get the flu shot when they get this shot the vaccine wont magically get rid of the virus but rather help them fight it off and protect them in the future if they keep up to date getting the vaccine
You cannot put your hand on a solid table because the particles are close together and in a fixed position. This is because the atoms of a solid are not like liquid, gas, and plasma. The particles are too condensed to move around an opposing force.
